A body is initially at rest. It undergoes one-dimensional motion with constant power. If its displacement, x is related to time, t as x = kt^p, where k is a constant, then what is the value of p?
This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
From the definition of Power in Mechanics, we can write the relation that:- P = F v P = m a v Using the relation that a = v d x d v . P = m v d x d v v P = m v 2 d x d v Integrating the above expression we get:- ∫ 0 x P d x = ∫ 0 v m v 2 d v P x = 3 m v 3 m 3 P x = v 3 d t d x = ( m 3 P x ) 3 1 x 3 1 d x = ( m 3 P ) 3 1 d t Again integrating both sides we get:- ∫ 0 x x 3 1 d x = ∫ 0 t ( m 3 P ) 3 1 d t 2 3 x 3 2 = ( m 3 P ) 3 1 t Now cubing both sides:- 8 2 7 x 2 = m 3 P m t 3 x 2 = 9 m 8 P t 3 x = 3 2 2 m P t t Hence we can write that:- x = k t 1 . 5
There is a typo in the fourth line of your solution. It should read as Pdx=mv^2dv. Also there is an extra m in the numerator in the last but 4 line.
Problem Loading...
Note Loading...
Set Loading...
P=ma.v
Given x=kt^p
So, a=ckt^(p-2) c=p(p-1) v=pkt^(p-1)
2p-3=0 , p= 1.5